For example, as sealing devices for use in pumps and valves, gland packings are known. As shown in FIG. 8, gland packings 93 are provided in annular space A between a housing 91 and a shaft 92 of a pump, and are sandwiched in an axial direction between a step 95 on an inner peripheral side of the housing 91 and a tubular tightening member 94 on an atmospheric side of the housing 91.
When the tightening member 94 is tightened to a fluid 99 side (inwardly in the axial direction) by a bolt 96, the gland packings 93 are compressed in the axial direction. While being further compressed, the gland packings 93 are closely contacted onto an inner peripheral surface 91a of the housing 91 and an outer peripheral surface 92a of the shaft 92. This can prevent the fluid 99 in the housing 91 from being leaked to the atmospheric side.
As such a gland packing, a packing having a band-like packing base material which is helically wound plural times is known (refer to Japanese Unexamined Patent Publication No. 6-201050 (see FIG. 1), for example). Further, the gland packing is formed with folded portions at axial ends of the packing base material layers overlapped in a diametrical direction. Penetration leakage in which a fluid enters into and passes through between the layers from axial end faces can thus be prevented.